From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx133.postini.com [74.125.245.133]) by kanga.kvack.org (Postfix) with SMTP id 23BF76B00E7 for ; Mon, 28 May 2012 11:21:43 -0400 (EDT) Received: from /spool/local by e28smtp04.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 28 May 2012 20:51:39 +0530 Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q4SFLYWx61669426 for ; Mon, 28 May 2012 20:51:35 +0530 Received: from d28av05.in.ibm.com (loopback [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q4SKq59u027223 for ; Tue, 29 May 2012 06:52:05 +1000 From: "Aneesh Kumar K.V" Subject: [PATCH] mm/hugetlb: Use compound page head in migrate_huge_page Date: Mon, 28 May 2012 20:51:30 +0530 Message-Id: <1338218490-30978-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, kamezawa.hiroyu@jp.fujitsu.com, mhocko@suse.cz, akpm@linux-foundation.org, rientjes@google.com Cc: linux-kernel@vger.kernel.org, "Aneesh Kumar K.V" From: "Aneesh Kumar K.V" The change was introduced by "hugetlb: simplify migrate_huge_page() " We should use compound page head instead of tail pages in migrate_huge_page(). Signed-off-by: Aneesh Kumar K.V --- mm/memory-failure.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) This is an important bug fix. If we want we can fold it with the not yet merged upstream patch mentioned above in linux-next. The stack trace for the crash is [ 75.337421] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 75.338386] IP: [] __mutex_lock_common+0xa1/0x350 [ 75.338386] PGD 1d700067 PUD 1d7dd067 PMD 0 [ 75.338386] Oops: 0002 [#1] SMP [ 75.338386] CPU 1 [ 75.338386] Modules linked in: ... ... [ 75.338386] Call Trace: [ 75.338386] [] ? try_to_unmap_file+0x38/0x51c [ 75.338386] [] ? try_to_unmap_file+0x38/0x51c [ 75.338386] [] ? vsnprintf+0x83/0x421 [ 75.338386] [] mutex_lock_nested+0x2a/0x31 [ 75.338386] [] ? alloc_huge_page_node+0x1d/0x55 [ 75.338386] [] try_to_unmap_file+0x38/0x51c [ 75.338386] [] ? alloc_huge_page_node+0x1d/0x55 [ 75.338386] [] ? arch_local_irq_save+0x9/0xc [ 75.338386] [] ? _raw_spin_unlock+0x23/0x27 [ 75.338386] [] try_to_unmap+0x25/0x3c [ 75.338386] [] ? console_unlock+0x210/0x238 [ 75.338386] [] migrate_huge_page+0x8d/0x178 diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 4a45098..53a1495 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1428,8 +1428,8 @@ static int soft_offline_huge_page(struct page *page, int flags) } /* Keep page count to indicate a given hugepage is isolated. */ - ret = migrate_huge_page(page, new_page, MPOL_MF_MOVE_ALL, 0, true); - put_page(page); + ret = migrate_huge_page(hpage, new_page, MPOL_MF_MOVE_ALL, 0, true); + put_page(hpage); if (ret) { pr_info("soft offline: %#lx: migration failed %d, type %lx\n", pfn, ret, page->flags); -- 1.7.10 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org